[PATCH V2 5/8] perf top: check per event overwrite term

[kan . liang]

From: Kan Liang <kan.liang@xxxxxxxxx>

Per event overwrite term is not forbidden in perf top, which can bring
problems. Because perf top only support non-overwrite mode.

Check and forbid inconsistent per event overwrite term in the evlist.
Make it possible to support either non-overwrite or overwrite mode.
The overwrite mode is forbidden now, which will be removed when the
overwrite mode is supported later.

Signed-off-by: Kan Liang <kan.liang@xxxxxxxxx>
---
 tools/perf/builtin-top.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 540461f..5e15d27 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -881,6 +881,56 @@ static void perf_top__mmap_read(struct perf_top *top)
 		perf_top__mmap_read_idx(top, i);
 }
 
+/*
+ * Check per event overwrite term.
+ * perf top supports consistent mode for all events.
+ * Return -1 if the per event terms set but not consistent.
+ */
+static int perf_top_overwrite_check(struct perf_top *top)
+{
+	struct record_opts *opts = &top->record_opts;
+	struct perf_evlist *evlist = top->evlist;
+	struct perf_evsel_config_term *term;
+	struct list_head *config_terms;
+	struct perf_evsel *evsel;
+	int set, overwrite = -1;
+
+	evlist__for_each_entry(evlist, evsel) {
+		set = -1;
+		config_terms = &evsel->config_terms;
+		list_for_each_entry(term, config_terms, list) {
+			if (term->type == PERF_EVSEL__CONFIG_TERM_OVERWRITE)
+				set = term->val.overwrite ? 1 : 0;
+		}
+
+		/* no term for current and previous event (likely) */
+		if ((overwrite < 0) && (set < 0))
+			continue;
+
+		/* has term for both current and previous event, compare */
+		if ((overwrite >= 0) && (set >= 0) && (overwrite != set))
+			return -1;
+
+		/* no term for current event but has term for previous one */
+		if ((overwrite >= 0) && (set < 0))
+			return -1;
+
+		/* has term for current event */
+		if ((overwrite < 0) && (set >= 0)) {
+			/* if it's first event, set overwrite */
+			if (evsel == perf_evlist__first(evlist))
+				overwrite = set;
+			else
+				return -1;
+		}
+	}
+
+	if ((overwrite >= 0) && (opts->overwrite != overwrite))
+		opts->overwrite = overwrite;
+
+	return 0;
+}
+
 static int perf_top__start_counters(struct perf_top *top)
 {
 	char msg[BUFSIZ];
@@ -890,6 +940,16 @@ static int perf_top__start_counters(struct perf_top *top)
 
 	perf_evlist__config(evlist, opts, &callchain_param);
 
+	if (perf_top_overwrite_check(top)) {
+		ui__error("perf top support consistent mode for all events\n");
+		goto out_err;
+	}
+
+	if (opts->overwrite) {
+		ui__error("not support overwrite mode yet\n");
+		goto out_err;
+	}
+
 	evlist__for_each_entry(evlist, counter) {
 try_again:
 		if (perf_evsel__open(counter, top->evlist->cpus,
-- 
2.5.5